Selective Coatings

Selective Coatings through Evolutionary Receptor Screening

The combination of the disciplines of materials science and bioengineering has provided the engineering of molecules for selective recognition. Majumdar and Lee Labs have discovered selective peptide motifs to distinguish TNT and DNT molecules through a directed evolution process of phage display. After four rounds of selection process using commercially available phage peptide library, we identified consensus binding peptide motifs for TNT and DNT molecules. Among the three consensus TNT binding peptide sequences, TNT1 sequence exhibited good selectivity for TNT molecules with little background for DNT. Identified peptide motifs for the TNT and DNT exhibited excellent specificity tested through phage binding assays. Using mutational analysis of TNT binding peptides (TNT1), we demonstrated that multivalent binding is the key to selectivity of the TNT binding motif. To make the discoveries relevant for gas phase chemical sensing, we created a biomimetic coating for highly selective detection of DNT in ambient conditions. We believe that this approach of evolutionary peptide screening followed by the creation of biomimetic coatings, when generalized for other target molecules, reflects a significant advance to enable highly selective and sensitive miniaturized chemical sensors.

Profiling High-Specificity Binding Partners

In order to improve the screening of selective chemical or biological receptors, (or affinity reagent) for sensing applications, a high throughput analysis method is needed. COINS researchers have harnessed the rapid, quantitative, binding specificity measurements to inform choice of affinity reagent selection. We utilize size and charge-based fractionation of multi-component samples with subsequent specificity measurement, in one unified assay. The measurement tool yields quantitative information regarding specificity (selectivity), affinity, and concentration with minimal consumption of precious phage-display products. This lends itself to rapid, quantitative assessment of affinity reagents necessary for selective aqueous sensors.Amy Herr (UCB), Seung-Wuk Lee (UCB) and Beth Pruitt (Stanford)